Higher-order cycloaddition processes are known in which transition metal mediated or transition metal templates are used in which the transition metal catalyst is used in stoichiometric amounts to provide cycloaddition products.
Publications are as follows:
1 Rigby and Ateeq, "Synthetic Studies on Transition-Metal-Mediated Higher Order Cycloaddition Reactions: Highly Stereoselective Construction of Substituted Bicyclo [4 4 1]undecane Systems" Journal of the American Chemical Society, 1990, 112.
2 Rigby and Henshilwood, "Transition Metal Template Controlled Cycloaddition Reactions. An Efficient Chronium(0)-Medicated [6.pi.+2.pi.] Cycloaddition", Journal of the American Chemical Society, 1991, 113.
The above publications, directed to the use of transition metal catalysts only in stoichiometric amounts, are incorporated by reference for their disclosure of triene, dienes and transition metal compounds including. chromium (0) complexes used in the transition metal mediated cycloaddition reactions.
It is desirable to provide an efficient cycloaddition process using only a small catalytic quantity of the expensive transition metal.